View clinical trials related to Long QT Syndrome.
Filter by:Each year world-wide, 2.5 million fetuses die unexpectedly in the last half of pregnancy, 25,000 in the United States, making fetal demise ten-times more common than Sudden Infant Death Syndrome. This study will apply a novel type of non-invasive monitoring, called fetal magnetocardiography (fMCG) used thus far to successfully evaluate fetal arrhythmias, in order to discover potential hidden electrophysiologic abnormalities that could lead to fetal demise in five high-risk pregnancy conditions associated with fetal demise.
Obstructive sleep apnea (OSA) has been associated with cardiac repolarization abnormalities and implicated in sudden cardiac death. A biologically plausible mechanism by which OSA exerts this lethality is by QT interval prolongation, a known marker of ventricular tachyarrhythmias (VTA) leading to cardiac death. Congenital long QT syndrome (LQTS) is a familial arrhythmogenic disorder characterized by prolonged QT interval on the electrocardiogram and increased propensity for VTA. Preliminary data identify an association of the extent of severity of OSA and progressive prolongation of the corrected QT interval in LQTS.
Studies have shown that the risk of developing heart arrhythmias, is increased in patients receiving medication for Attention-deficit hyperactivity disorder (ADHD) and depression. The QT-interval on a electrocardiogram (ECG) is often used to assess the patients risk of developing heart arrhythmias. The QT-interval defines the hearts electrical resting period and a long interval is linked to an increased risk of developing heart arrhythmias. In this project the investigators wish to examine possible side-effects in patients receiving medication for ADHD and depression and their dynamic QT-interval changes, by analysing the ECG changes that occur during "Brisk Standing".
The Long QT syndrome is associated with potentially life-threatening cardiac arrhythmias as ventricular tachycardia (Torsade de pointes) as well as ventricular fibrillation, and might lead to syncope as well as sudden cardiac death (1). Good results have been achieved by treating patient at risk with beta blockers and implantable cardiac defibrillator (ICD). It is therefore important to diagnose the condition as early as possible as the disease is treatable (2). Prolonged QT duration might also be induced by the intake of numerous pharmaceutical substances, as well as with electrolyte disturbances, which also increases the risk of life-threatening cardiac arrhythmias. Furthermore, congenital LQTS can arise from mutations in one of at least 13 different genes. Many of these genes encode proteins which are constituents of ion channels. The genetically defined long QT syndrome has autosomal dominant (Romano Ward Syndrome) or autosomal recessive (Jervell and Lange-Nielsen Syndrome) inheritance. In this study we are using the hospital ECG database obtained with the GE Marquette 12SL ECG Analysis Program® at Telemark Hospital Skien recorded between March 2004 and April 2014. This database stores approximately 200 000 ECG recordings from 60 000 unique patients. By using the search algorithm in the MUSE ECG database, 2398 recordings have been be identified from 1603 patients where the corrected QT time is longer than 500 ms, and QRS is less than 120 ms. ECG recordings with QT intervals longer than 500 ms represents less than 1% of the population (5). Individuals having these recordings are selected for extensive clinical follow up. The patients will be offered the opportunity to have genetic analysis performed in order to distinguish between inherited or acquired long QT syndrome. The appropriate treatment will be initiated according to guidelines for patients with inherited QT syndrome. For patients with aquired long QT syndrome substitution of unfavourable pharmacotherapy or correction of electrolytes shall be performed in order to reduce their risk of cardiac arrhythmias. A T wave morphology score gives independent prognostic information useful for risk stratification. The purpose of this substudy is to examine if the T wave morphology score applied on the 1531 patients ECGs with QTc >500 ms, has independent prognostic value in this cohort.
The projects will try and optimise the risk stratification for patients with Long QT syndrome by investigating how the exposure of physical and acoustic stress will affect the QT-dynamics and if beta blockers protect against arrhythmias by suppressing this dynamic QT-prolongation. Furthermore, the project will investigate the effects of Spironolactone on the QT-dynamics tested by "Brisk Standing". First, patients are tested with known arrhythmic triggers and they are then administered thier normal dose of beta blockers. Hereafter, "Brisk Standing" test is performed and the patients are on Spironolactone for seven days. After seven days treatment the "Brisk Standing" is repeated.
Patients with cardiac channelopathies needing restorative dental treatment will be included in two sessions of the study, using local dental anesthetic: lidocaine 2% with epinephrine and lidocaine 2% without vasoconstrictor. The safety of the use of two cartridges (3.6 mL) will be evaluated. The patients will be their own control and will be assessed by Holter monitoring for 28 hours, blood pressure measurement and anxiety measuring.
.Cardiac affection in liver cirrhosis is a clinical condition characterized by impaired diastolic relaxation and contractility with electrophysiological abnormalities. .Cirrhotic patients with cardiac abnormality have higher mortality rates compared to patients without cardiac affection. The suggested pathophysiologic mechanisms of cardiac affection in cirrhotic patients are; alterations in the beta-adrenergic signaling pathway and, myocardial fibrosis formation, sympathetic nervous system activation and changes in ion channels. .As a component of cardiac involvement in cirrhotic patients fragmented QRS complex and prolongation of the corrected QT interval has been documented in most of the cases with liver cirrhosis (LC) and its prevalence increases with the severity of the disease
This study will assess whether exposure response analysis of the electrocardiographic QTc and J-Tpeakc intervals in Phase 1 clinical pharmacology studies can be used to confirm that drugs that predominantly block the potassium channel encoded by the human ether-à-go-go-related gene (hERG) with approximately equipotent late sodium and/or calcium block ("balanced ion channel" drugs) do not cause J-Tpeakc prolongation and that drugs that predominantly block hERG without late sodium or L-type calcium current block ("predominant hERG" drugs) cause QTc prolongation.
The postnatal diagnosis of Long QT Syndrome (LQTS) is suggested by a prolonged QT interval on 12 lead electrocardiogram (ECG), strengthened by a positive family history and/or characteristic arrhythmias and confirmed by genetic testing. However, for several reasons such LQTS testing cannot be performed successfully before birth. First, fetal ECG is not possible and direct measure of the fetal QT interval by magnetocardiography is limited to fewer than 10 sites world-wide. Second, while genetic testing can be performed in utero, there is risk to the pregnancy and the fetus. Third, although some fetuses present with arrhythmias easily recognized as LQTS (torsade des pointes (TdP) and/or 2° atrioventricular (AV) block, this is uncommon, occurring in <25% of fetal LQTS cases. Rather, the most common presentation of fetal LQTS is sinus bradycardia, a subtle rhythm disturbance that often is unappreciated to be abnormal. Consequently, the majority of LQTS cases are unsuspected and undiagnosed during fetal life, with dire consequences. For example, maternal medications commonly used during pregnancy can prolong the fetal QT interval and may provoke lethal fetal ventricular arrhythmias. But the most significant consequence is the missed opportunity for primary prevention of life threatening ventricular arrhythmias after birth because the infant is not suspected to have LQTS before birth. The over-arching goal of the study is to overcome the barriers to prenatal detection of LQTS. The investigators plan to do so by developing an algorithm using fetal heart rate (FHR) which will discriminate fetuses with or without LQTS. Immediate Goal: The investigators propose a multicenter pre-birth observational cohort study to develop a Fetal Heart Rate (FHR)/Gestational Age (GA) algorithm from a cohort of fetuses recruited from 13 national and international centers where one parent is known by prior genetic testing to have a mutation in one of the common LQTS genes: potassium voltage-gated channel subfamily Q member 1 (KCNQ1), potassium voltage-gated channel subfamily H member 2 (KCNH2), or sodium voltage-gated channel alpha subunit 5 (SCN5A). The investigators have chosen this population because 1) These mutations are the most common genetic causes of LQTS, and 2) Offspring will have high risk of LQTS as inheritance of these LQTS gene mutations is autosomal dominant. Thus, progeny of parents with a known mutation are at high (50%) risk of having the same parental LQTS mutation. The algorithm will be developed using FHR measured serially throughout pregnancy. All offspring will undergo postnatal genetic testing for the parental mutation as the gold standard for diagnosing the presence or absence of LQTS.
On 04/30/2015, ANSM (the National Security Agency of Medicines and Health Products) shared an information for general practicioners, pediatricians, anesthesiologists, dermatologists, geriatricians, psychiatrists, community pharmacists and hospital about using hydroxyzine and the associated risk of QT prolongation on the electrocardiogram. Drugs containing hydroxyzine (the best known and most used is the Atarax®) are used in France in various indications including the treatment of minor manifestations of anxiety, premedication with general anesthesia and the symptomatic treatment of urticaria. A prolonged QT interval is a known risk factor for occurrence of torsades de pointes which can cause sudden death. We distinguish congenital and acquired long QT interval. The main cause of acquired long QT interval is a drug inhibition of the HERG potassium channel 1. Many drugs have been reported to cause sudden death by prolongation of QT interval and occurrence of torsades de pointes (macrolides, anti -arythmics, some psychotropic ...) The molecules based on hydroxyzine are known to be at risk of prolongation of QT interval in an experimental point of view but is not clearly identified in daily clinical practice. Pharmacology unit of Caen was the first to publish a case of QT prolongation under hydroxyzine . Through this publication, associated with other clinical data, hydroxyzine has been added to the list of drugs that can induce QT prolongation . Despite these recent recommendations, it does not seem that hydroxyzine prescriptions were changed daily and therefore the risk of QT prolongation persists. We therefore propose the study of the impact of hydroxyzine on the QT interval measured on the electrocardiogram in patients hospitalized at the University Hospital of Caen.